3-chloropropyl diisopropylthiolcarbamate



United States Patent Ofiice 3,305,576 Patented Feb. 21, 1967 3,305,576S-CHLOROPROPYL DIISOPROPYLTHIOL- CARBAMATE John J. DAmico, Charleston,and Marion W. Harman,

Nitro, W. Va., assignors to Monsanto Company, a corporation of DelawareNo Drawing. Original application July 10, 1959, Ser. No. 826,130.Divided and this application Nov. 13, 1962, Ser. No. 246,170

1 Claim. (Cl. 260-455) This application is a division of applicationSerial No. 826,130, filed July 10, 1959.

The present invention relates to methods of controlling or destroyingvegetation and to phytotoxic haloalkyl thiolcarbamates.

The toxicants employed in the practice of the present invention containthe nucleus where A represents a halogen substituted alkyl group,preferably a chloro or bromo substituted lower alkyl group, but fluorineand iodine are also suitable, and R represents a secondary amino group,nitrogen of which is linked to the carbonyl radical. A wide variety ofsecondary amino radicals are suitable, as for example morpholinyl,pyrr-olindinyl, piperidinyl, lower alkyl substituted derivatives ofthese radicals, 4-phenylpiperazinyl, disubstituted amino radicals inwhich the substituents are lower alkyl, lower alkenyl, cyano substitutedlower alkyl, halogen substituted lower alkenyl, lower alkoxy substitutedlower alkyl, lower alkoxy substituted lower alkyl, phenoxy substitutedlower alkyl, combinations of these radicals or combinations of one ofthem with higher alkyl, propargyl, cyclohexyl, cyclohexenyl, phenyl,benzyl, furfuryl or tetrahydrofurfuryl. By alkenyl radical is meant anunsaturated acyclic radical the unsaturation of which consists in onedouble bond. It will be noted that the nitrogen of the amino group inthe above formula is attached to three different carbon atoms, hydroxyon the nitrogen being absent. Preferably not more than one phenyl,cyclohexyl or benzyl group is present but combinations with otherradicals have proved to be very desirable.

Examples of the toxicants comprise 2-ch1oroethyl, 2-bromoethyl,2-iodoethyl, 2-fluoroethyl, chloromethyl, 2,3-dichloro-2-methylpropyl,3-chloropropyl, 2-chloropropyl, 2-chlorobutyl, 2-chloroamyl,2,3-dichloropropyl, and 2,3 dibromopropyl esters of the followingthiolcarbamic acids: dimethyl-, diethyl-, dipropyl-, diisopropyl-,dibutyl-, diisobutyl-, diallyl-, N-allyl-N-isopropyl-, Nmethyl-N-cyclohexyl-, N-ethyl-N-cyclohexyb, di(methoxyethyl)-,di(methoxypropyl)-, N (2 cyclohexenyl)-N-isopropyl-, N-(2cyanoethyl)-N-isopropyl-, N (2 chloroallyl)-N-isopropyl-, N (2chloroallyl)- N 3-Inethoxypropyl-, di(ethoxypropyl)-,di(2-phenoxyethyl)-, N-ethyl-N-Z-phenoxyethyl-, di(2 chloroally1)-, Nethyl-N vinyloxyethyland N-ethyl-N-isopropoxypropylthiolcarbamic acids,4 morpholinecarbothiolic acid, 1 pyrrolidinecarbothiolic acid, 4 phenyllpiperazinecarbothiolic acid, 1 piperidinecarbothiolic acid,Z-methyl-l-piperidinecarbothiolic acid, 5-ethyl 2- methyl 1piperidinecarbothiolic acid, 5-ethyl-3-methyll-piperidinecarbothiolicacid, 2,4,6-trimethyl-l-piperidinecarbothiolic acid and 2,6dimethylmorpholinecarbothiolic acid.

The compounds employed in the practice of this invention are newcompounds. Preparation of the new toxicants is illustrated in detailbelow.

Example 1 There was charged to a reactor 110 parts by weight of 88%diisopropylamine, 200 parts by Weight of water and 160 parts by weightof 25% sodium hydroxide. The charge was cooled to 0 C. and stirred while78 parts by weight of 85% COS was bubbled in over a period of about anhour. The reaction mixture was kept below about 10 C. during theaddition. There was then added in one portion 236.2 parts by weight of3-chloropropylbromide. The reaction mixture was stirred at 2530 C. for24 hours and then extracted with ethyl ether. The ether extract wasfiltered to remove sodium chloride, washed with water until neutral tolitmus, dried over sodium sulfate and the ether removed in vacuo at amaximum temperature of 90 C. at 1-2 mm. There was obtained 141 parts byweight of an amber oil. This was distilled in vacuo, the fractionboiling at 132- 134 C. and 3.5 mm. being collected. It contained 5.8%nitrogen and 13.8% sulfur as compared to values calculated for3-chloropropyl diisopropylthiolcarbamate of 5.9% nitrogen and 13.5%sulfur.

Example 2 There was charged to a reactor 180 parts by weight of 25%dimethylamine and 160 parts by weight of 25% sodium hydroxide. Themixture was cooled to 0 C. and 78 parts by weight of COS bubbled in at0l0 C. over a period of about an hour. There was then added 236.2 partsby weight of 3-chloropropylbromide and stirring continued for 24 hours,the temperature during this phase of reaction being 25-30 C. Thereaction mixture was then extracted with ethyl ether and the ethersolution washed with water until neutral to litmus, dried over sodiumsulfate and the ether removed in vacuo. The residue was distilled invacuo, collecting the fraction boiling at -126" C. at 4 mm. pressure.The product contained 7.6% nitrogen, 18.0% sulfur and 20.0% chlorine ascompared to values calculated for 3-chloropropyl dimethylthiolcarbamateof 7.7% nitrogen, 17.7% sulfur and 19.5% chlorine.

Example 3 In the procedure of Example 1, 101.1 parts by weight ofdipropylamine was substituted for 110 parts by weight ofdiisopropylamine. 3-chloropropyl dipropylthiolcarbamate was obtained asan oil, boiling point -147 C. at 3 mm. pressure. It contained 5.8%nitrogen, 13.3% sulfur and 15.5% chlorine as compared to calculatedvalues of 5.9% nitrogen, 13.5% sulfur and 14.9% chlorine.

Example 4 In the procedure of Example 1, 73.2 parts by weight of diethylamine was substituted for 110 parts by weight of 88% diisopropylamine,3-chloropropyl diethylthi-olcarbamate was obtained as an oil boilingpoint 148-150 C. at 10 mm. pressure. It contained 6.4% nitrogen, 15.3%sulfur and 16.5% chlorine as compared to calculated values of 6.7%nitrogen, 15.3% sulfur and 16.9% chlorine.

Example 5 There was charged to a reactor 110 parts by weight of 88%diisopropylamine, 200 parts by weight of water and parts by weight of25% sodium hydroxide. This mixture was cooled and stirred at 05 C. whileadding to it 78 parts by weight of 85% COS over a period of about one'and one-half hours. There was then added 375.8 parts by weight ofethylene dibromide in one portion. External cooling was discontinued andthe reaction mixture stirred at 2530 C. for 24 hours. The reactionmixture was extracted with ethyl ether, the ether extract dried oversodium sulfate and the ether removed in vacuo. The excess of1,2-dibromoethane was removed by atmospheric distillation at a maximumpot temperature of 200 C. The residue was distilled in vacuo, collectingthe fraction boiling point 136l38 C. at 4 mm. The distillate solidifiedupon standing. The product was dried on a porous plate at 25-30 C. Itwas a white solid melting at 51- 53 C. Analysis gave 5.2% nitrogen, thevalue calculated for 2-bromoethyl diisopropylthiolcarbamate.

Example 6 There was charged to a reactor 103.4 parts by weight of 98%diisopropylamine, 160 parts by weight of 25 sodium hydroxide and 200parts by weight of water. The mixture was stirred and cooled to C. andto it at O C. 78 parts by weight of 85% COS was added over a period ofabout one and one-half hours. External cooling was discontinued, 254.4parts by weight of 1,4-dichlorobutane added in one portion and thereaction mixture stirred at 2530 C. for 24 hours. Thereupon there wasadded 400 parts by weight of water, stirring continued for minutes, thebottom organic layer separated and dried over sodium sulfate. The excessof 1,4-dichlorobutane was removed by atmospheric distillation until thepot temperature reached 200 C. The residue was distilled in vacuocollecting the fraction boiling point 141- 143" C. at 2 mm. pressure. Itcontained 5.5% nitrogen, the calculated value for 4-chlorobutyldiisopropylthiolcarbamate.

Example 7 In the procedure of Example 5 there was substituted 215.2parts by weight of 2-chlor0ethylbromide for the 1,2-dibromoethane. Theprocedure was the same except that the excess 2-chloroethylbromide wasremoved by atmospheric distillation at a maximum pot temperature of 185C. The product boiled at 1l6118 C. at 2 mm. pressure. Upon standing itsolidified. After drying on a porous plate the melting point was 3739 C.Analysis gave 6.2% nitrogen, 14.4% sulfur and 15.3% chlorine as comparedto values calculated for 2-chloroethyl diisopropylthiolcarbamate of 6.3%nitrogen, 14.3% sulfur and 15.9% chlorine.

Example 8 There was charged to a reactor 31.8 parts by weight ofN-ethylcyclohexylamine, 50.0 parts by weight of water and 40 parts byweight of sodium hydroxide. The charge was cooled to 0 C. and stirredwhile 19 parts by weight of 85% COS was bubbled in. The reaction mixturewas kept below 10 C. during the addition. There was then added in oneportion 47.3 parts by weight of 3-chl0r0pr0pylbromide.' The reactionmixture was stirred at 245-" C. for 24 hours and then extracted withethyl ether. The ether extract was filtered to remove sodium chloride,washed with water until neutral to litmus, dried over sodium sulfate andthe ether removed in vacuo at a maximum temperature of 8090 C. at 1-2mm. There was obtained 55 parts by weight of amber liquid whichcontained 5.00% nitrogen, 12.51% sulfur and 13.67% chlorine compared to5.31% nitrogen, 12.15% sulfur and 13.44% chlorine calculated for3-chloropropyl N-ethyl- N-cyclohexylthiolcarbamate.

Replacing N-ethylcyclohexylamine by 34.8 parts by Weight ofN-isopropylcyclohexylamine in the foregoing procedure yield 43 parts byWeight of amber liquid which contained 4.96% nitrogen compared to 5.04%nitrogen calculated for 3-chloropropylN-isopropyl-N-cyclohexylthiolcarbamate. r

Replacing N-ethylcyclohexylamine by 28.3 parts by weight ofN-methylcyclohexylamine and 3-chloropropylbromide by 43 parts by weightof 2-chloroethylbromidein the foregoing procedure yield 34 parts byweight of amber liquid which contained 5.69% nitrogen compared to 45.94% nitrogen calculated for 2-chloroethyl N-methyl-N-cyclohexylthiolcarbamate.

The most effective control was observed from pre-emer gent applicationwhereby the toxicants were brought into contact with germinatingseedlings but they are also somewhat toxic to foliage. By application tovegetation is meant either application to the soil before the plantsemerge or to the foliage. The toxicants may be applied to the soil or tofoliage conveniently in the form of a spray containing the activeingredient in a concentration within the range of 0.1%5.0%. Forpre-emergence application amounts within the range of 1 to 60 pounds peracre are recommended. The active components are insoluble in water butthey are soluble in common organic solvents. They may be disperseddirectly in water or dissolved first in an organic solvent and thendispersed. As dispersing and wetting agents there may be employed softor hard sodium or potassium soaps, alkylated aromatic sodium sulfonatessuch as sodium dodecylbenzenesulfonate, or an amine salt ofdodecylbenzenesulfonic acid, alkali metal salts of sulfated fattyalcohols, ethylene oxide condensation products of alkyl phenols or talloil and other dispersing and wetting agents. The herbicides may beformulated and applied as dry compositions by mixing the toxicant with afinely divided or granular solid carrier, as for example talc, clay,pyrophyllite, silica and fullers earth. Alternatively, the drycomposition may be dispersed in water and applied as a spray.

As illustrative of the practice of the invention the toxicants wereapplied as aqueous sprays to a variety of germinating seedlings. Theactive ingredient was emulsified in water and applied to the soil ofseeded plots at the rate shown before the grass or other plants emerged.The plants employed in the test are designated by letter. The plantscorresponding to the letters are as follows:

A-Morning glory HCrabgrass B-Wild oats J-Pigweed C-Bromegrass KSoybeanD-Ryegrass LWild buckwheat EMustard (radish) MTomato F-Sugar beetN--Sorghum GFoxtail For convenience in recording the data the followingrating key was used:

No phytotoxicity 0 Slight phytotoxicity 1 Moderate phytotoxicity 2Severe phytotoxicity 3 TABLEI Phytotoxicity Rating Dosage Lbs/AcreBCDEFGHJKLMN In pre-emergence application at 25 pounds per acre3-chloropropyl dipropylthiolcarbamate exerted severe phytotoxicity tomorning glory, wild oats, bromegrass, ryegrass, foxtail, crabgrass andpigweed. Similar results were observed with 3-chloropropyldiethylthiolcarbamate, 3-chloropropyl dimethylthiolcarbamate and4-chlorobutyl diisopropylthiolcarbamate. Again the effectiveness of lowrates of application was extended by incorporating the PO-IOSO (5/69)Patent No. 3 ,305 76 Inventor(s) UNITED STATES PATENT OFFICE CERTIFICATEOF CORRECTION Dated February 21 1967 John J. D'Amico and Marion W.Harman It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

Column 1, lines 1820, the formula should read as f llow-sz Column 2 line55 cancel 3-ch1oropropy1" and insert in place thereof (SEAL) .Attest:

Edward M. Fletcher, J r,

Attesting Officer 3-Chloropropyl SIUNED AND SEALED NOV 4 1969 WILLIAM E.SUHUYLER, JP Commissioner of Patent:

